The timing of email marketing campaigns is an age-old debate for those in the industry. Everyone wants to optimize the timing to improve open rates and sales. "It's not necessarily the best day, but when can you stand out in the inbox," says Morgan Stewart, cofounder and CEO of Trendline Interactive, a marketing consulting firm. "It's nice to be the one thing sitting at the top of the inbox."

Ideal timing varies dramatically by company, notes Stewart. A pizza company might realize that Friday at 4 pm is the best time to tempt its customer base with a pizza special. Or a motorcycle gear company might send emails on Saturdays when its customers think about motorcycle rides. Stewart says that the best way for companies to get ahead is to try to understand their target market and how their product meets those customers' needs.

The timing of email campaigns definitely impacts campaign results, says Michael Feiman, president of PoolDawg.com, a Colorado-based online retailer of billiard supplies. The company settled into sending its 50,000 weekly emails late morning on Tuesdays after experimenting with each of the seven days and different times. As a result, PoolDawg increased its open rates 200%, as well as tripled its conversion and click-through rates. "We've looked at our sales patterns and Web traffic as well to see when customers are ready to place an order," Feiman relates. "Customers are far more likely to open an email if they are already online."

Confidently schedule email

Look at the time and date stamp. When are your customers
signing up for your emails? That will provide a better idea
of when to reach your customers.

Link email analytics to sales. If your best email open time
doesn't correlate to when people buy the most, follow
the sales timetable. This is the more important number.

Understand mobile. Determine how many of your
customers open email on smartphones and optimize
creative to appear on these devices.

Email service providers allow time testing. The more
emails you send, the more chances to experiment and
you'll learn faster.

Nonprofit organizations, like Pittsburgh-based SponsorChange.org, rely on email marketing to gather volunteers and donations. This social enterprise sends 7,000 to 10,000 emails one to two times a month to its database to inform them of current projects and ways to get involved. After testing various times that fit its target market, the nonprofit realized that 9 am and 1 pm produced the best response. It achieved a 30% to 40% response from emails over a month-long period. When it sent emails at 4 pm or after, it might have received eight or nine responses out of thousands.

Global design company, Igigi by Yuliya Raquel, a designer of plus-size clothing, considers its international audience when sending email campaigns. With customers in North America, Europe, the Asia Pacific and Australia, Igigi sends 50,000 emails twice a week between 4 am and 6 am PST. The company releases new products each Tuesday and Thursday and announces them with an email.

"After trial and error for years with A/B testing, this time works best," says Alex Brodsky, Igigi's CEO and VP of marketing. "We are achieving an open rate of 11% to 12% and a conversion rate of 50% of those who open the email. But a great subject line is just as important to get people to open emails."

Dan Zarrella, social media scientist at HubSpot, an Internet marketing firm outside Boston, is well-known for his email marketing research, "The Science of Timing"and "The Science of Email Marketing," based on 9.5 billion emails sent over a four to five year period. Zarrella partnered with MailChimp for the research and also conducted his own focus groups.

The bottom line from Zarrella and others is to gather best practices from industry research and then apply it to your individual brand. "People are just guessing based on what feels right, and it's not based on real data," he says. "If marketers want to get exceptional results, they must start using data. Use these best practices as a starting point, but experience testing and closed loop reporting are super important."